JLCat is right,
You are not alone!!! I assure you that there has been many people here that have reached rock bottom as you have right now, and have been able to get this disease under control.
Unfortunately, it sounds like your disease was out of control for many years untreated. At this point, Pentasa for you is likely useless. The descending prednisone should help get you feeling better, but the Imuran doesn't sound like it's at a high enough therapeautic dose. You need to have a metabolite test to get the optimal dosing of that.
You are very likely ready to make the move to biologics. I would think that your GI would discuss Remicade with first, but Humira is good as well.
I know that you said that the positive thing isn't working, but you have to keep trying. You have kids to care for, and it sounds like you're a very good father. Good luck, I promise you things will get better soon.